Automatic fuel regulator



Sept. 15, 1936.

c. sToKEs AUTOMATIC FUEL REGULATOR Original Filed Sept. l, 1927 3Sheets-Sheet 1 sept. 1 5, 1936-. CY STKES Re. 20,112

AUTOMATIC FUEL REGULATOR original Filed sept. 1,'192'7 5 sheets-sheet:2L

Reissued Sept. 15, 1936 UNITED STATES PATENT OFFICE l AUTOMATIC FUELREGULATOR Original No. 1,841,687, dated January 19, 1932,

Serial No. 216,918, September 1, 1927.

Application for reissue January 18, 1934, Serial-No.

36 Claims.

This invention relates to improvements in automatic fuel regulation forinternal combustion engines.

The principal object of the invention is to provide automatic control ofthe fuel supply from a carbureter to an internal combustion engine towhich the carbureter is attached.

Another object of the invention is to provide automatic fuel regulationthrough a carbureter to an engine controlled by thev heat of the engine.

Another object is to provide automatically controlled choking and/orpriming means for a. carbureter.

Another object is to provide automatic control of the main throttlevalve of a carbureter at starting.

Another object is to provide a thermostatically controlled carbureterfor aninternal combustion engine.

Another object is to provide a thermostatically controlled means ofregulating the supply of fuel and air to an engine.

Other objects will become apparent as my invention is more fullydisclosed herein.

Referring to the drawings, wherein the same numbers indicate like parts:

Fig. 1 is a plan view of a carbureter.

Fig. 2 is a section along the lines 2 2 of Fig. 1.

Fig. 3 is a section of part of Fig. 2.

Fig. 4 is a modification of part of Fig. 2.

Fig. 5 is a section along the lines 5 5 of Fig. 2.

Fig. 6 is a section along the lines 6-6 of Fig. 5.

Fig. 7 is an alternative for part of Fig.` 5.

Fig. 8 is a detail of improved construction for application to Figs. 1,2, 5, and '7.

Fig. 9 is an alternative for Fig. 8.

Fig. 10 is a section along the lines I 0--I0 of Fig. l.

Fig. 11 is a view along the lines II-II of Fig. 10.

Fig. 12 is a view along the lines I2-I2 of Fig. 10.

Fig. 13 is a side view of amodication of Fig. 1.

Fig. 14 is a view of the carbureter attached to an internal combustionengine.

Fig. 15 is a section along the lines I5-I5 of Fig. 14.-

Fig. 16 is an alternative to part of Fig. 14.l

Fig. 17 is an alternative to part of Fig. 14.

Fig. 18 is a view of part of Fig. 17.

An internal combustion engine I0 is provided With an inlet manifold IIand an exhaust pipe A carbureter I3 is fixed to manifold II forsupplying air and .fuel in regulated and variable (Cl. 12S-119)quantities to engine I0 responsive to the engine suction and a hot airstove I4 surrounds pipe I2 being connected by a flexible pipe I5 to themain air entry I6 of carbureter I3, air being admitted to the interiorof stove through a port I'I. .Liquid fuel is supplied in any well knownmanner to carbureter I3 through a pipe I8, all as illustrated in Figs.14 and 15.

Referring now to Figs. 1, 2, 3, 5, 6, 10, 11 and l2, carbureter I3 isprovided With the usual constant level float chamber I9 which receivesliquid fuel through pipe I8, the level of which is controlled by float20 to which is attached a valve (not shown) governing the entry of pipeIB to chamber I9.

Carbureter I3 is attached to engine Ill and the engine suction draws airin through main air entry IE to a mixing chamber 2| where fuel is mixedtherewith and supplied to engine I0 in regulated and variable quantitiesby a throttle valve 22. The main liquid fuel supply is drawn fromchamber I9 through a port 23 to a regulating port l2li controlled by aneedle valve 25 and thence through a passage 26 to a fitting 21 where itis mixed with a secondary air supply drawn through a passage 28 to asecondary mixing chamber 29 and discharged through main nozzle 30 to themain mixing chamber 2|.

The discharge of nozzle 3II is set at the throat of a small Venturi tube3I,`held in carbureter I3 by apart 32, and the discharge of venturi 3|is set at the throat of a large Venturi tube 33 the upper part of whichforms the lower part,

of mixing chamber 2|. Secondary air is supplied to a passage 28 from airentry I6 through a port 34, the flow therethrough being governed by avalve 35 Working in a cylinder 36. Valve 35 is normally seated by spring31 held in passage 36 by a plug 38 and is lifted from its seat by theengine suction applied to cylinder 36 through a port 39 on the engineside of throttle 22 and this suction can be regulated by a screw 40controlling the entry of air through a port 4I in the form of an airbleed.

The usual idling mixture is provided by the supply of liquid fuel frompassage 26 through a. passage 42 which leads to a discharge orifice 43in the mixing chamber on the engine side of throttle 22, the admissionof idling air being regulated by an adjusting screw 44 controlling theadmission of air through a port 45, and the idling mixture is rsuppliedonly at such times as throttle 22 is substantially closed or ashereinafter described.

Throttle 22 is held in a spindle 46 which is journalled in the walls ofcarbureter I3, one end being surrounded by a sleeve 41 on which ispressed a throttle arm 48. A slot 49 is formed in spindle 46 to permit acertain degree of movement thereof with respect to throttle arm 48 and apin 58 passes through arm 48, sleeve 41 and spindle 46 for transmittingmotion from arm 48 to spindle 46, there being no lost motion between pin58, arm 48 and sleeve 41.

To the opposite end of spindle 46 is attached a secondary throttle arm5I, whereby a limited movement of spindle 46 and throttle 22 withrespect to arm 48 may be effected at starting periods, the movementdepending on the angularity in the walls of slot 49, and a startinglever 52 fastened by screw 53 to eiiect said movement initially. l

The other end of lever 52 rests on the upper part of a dashpot 54containing a reciprocating piston 55 pressed on a stem 56. The lowerpart of dashpot 54 is open to atmosphere through a port 51 and the underside of piston 55 is cushioned against a spring 58. Stem 56 is hollowand a plurality -of ports 59 through the walls thereof connect the spacebetween the upper side of piston 55 and the upper wallof dashpot 54 withair passage I6; dashpot 54 being threaded at its lower end to screw intoa boss 68.

This last end of spindle 46 passes through the upper part of anaccelerating well 6I containing a tube 62 lopen at its lower end toreceive liquid fuel through a passage 63 from chamber I9 and its upperend connecting with a passage 64, and a minute orifice 65, to mixingchamber 2| on 'the engine side of throttle 22. Tube 62 is xed at itsupper end in the casting to have an annular space 66 therearoundconnected to atmosphere by a port 61 and through a passage 68 in part 32to a discharge orifice 69 in venturi 3|, it being here noted that port61, passage 68, orifice 69, nozzle 38 and air port 34 are all above thenormal constant liquid level X-X in fioat chamber I9.

A choke valve 18 is mounted off center in passage I6 on a spindle 1Lhaving its ends journalled in bosses 12 and 13.. Boss 13 is encircledby a casing 14 adjustably held thereon by a screw 15 working in a slot16 and having its outer end closed by a cover 11. Interiorly of casing14 is a bimetallic thermostatic spring 18 having one end ailxed in aslot in spindle 1 I, the other end being fastened to casing 14 by bolt19 and nut 88. A regulating disk 6I, xed to spindle 1I, serves to openand close a passage 82 connecting the invterior of casing 14 withpassage I6 through boss 13 onvthe engine side of choke valve 18, theopening and closing being effected by the relative position of a slot 83cut in disk 8|. A second passage 84 serves to connect the interior ofcasing 14 with 'airpassage I6 on the atmosphere side of choke valve 18being continuously open by means of a slot 85 cut in disk 8.I, its otherend terminating in `animpact pipe 81 having its atmosphere vside cutaway at 86 and standing to such a height in passage I6 as to form a stopfor choke valve 18 when wide open and in a horizontal position. Theupper part of accelerating well 6I has passage 64 therein connected toatmosphere through passage 88 closed by a plug 89 having an orifice ofpreldeterminedsize therein to regulate the height to -is substantiallyunrestrictedly open, throttle 22 is held closed at idling position by aspring 98 fastenedyto one end of a cross bary 9i extending across thecover of float chamber I9, a second spring 92 fastened to the oppositeend of bar 9I serving to apply the proper tension to arm 48 for holdingthrottle 22 at idling position. Float chamber I9 is open to amosphericpressure through a port 93.

The operation of the devices already illustrated and described whenattached in operative position to an internal combustion engine is asfollows:

If it be assumed that engine I8 is cold and at low temperaturethermostatic spring 18 will be contracted to hold choke valve 18 closedin passage I6 except for a very slight leak around the periphery ofvalve 18. Throttle 22 is held closed at idling position. Upon crankingengine I8, the suction thereof is transmitted past throttle 22 throughstem 56 and holes 59 to the upper part of piston 55 whereby the same israised thereby lifting lever 52 and opening throttle 22 a predeterminedamount against the resistance of spring 98. The amount of opening ofthrottle 22 will be determined by the degree of angularity of the wallsof slot 49 in spindle 46. In this manner a comparatively high suction isapplied to nozzle 38 for drawing therethrough a rich priming charge ofliquid fuel which is unmixed with air in fitting 21 because-substantially the same vacuum 'exists at nozzle 38 as there is at port34 when choke valve 1n is closed. At the same time a umited amount ofair and liquid fuel is supplied through orifice 43. This rich primingcharge, which isdue to the limited amount of air passing choke valve 18,is drawn into the cylinders of engine I8 by its suction until themixture isignited therein, whereupon a sudden increase in vacuum takesplace in mixing chamber 2| because engine I8 will be then idling atincreased idling speed over cranking speed and this increase in vacuumcauses a partial opening of choke valve 18 against the resistance ofthermostatic spring 1B because of the difference in pressure now exertedon opposite sides of valve 18, valve 18 being mounted on spindle 1I oi'center in passage I6.

Throttle 22 being held open beyond normal idling position apredetermined amount by lever 52, engine I8 runs at a fast rate becauseit is necessary to idle fast at low temperatures and the engine .vacuumis applied through passage 82 to the interior of casing 14 wherebyheated air is drawn thereto from stove I4 through pipe I5, pipe 81 andpassage 84, it beingnoted that at cranking speeds passage 82 is entirelyclosed by disk 83 so that the highest effective Vacuum will be appliedfor drawing in a rich priming charge from nozzle 38, the sudden increasein vacuum upon the engine I8 firing causing the initial partial openingof passage 82 whereby heated air will commence to be drawn therethrough.With continued running of engine I8, the air drawn through casing 14 andover thermostatic spring 18 therein will cause continued expansion ofsaid thermostat thus causinga gradual and continued opening of chokevalve 18 and a gradual and continued decrease of vacuum applied to thetop of piston 55 whereby spring 98 gradually closes throttle 22 untilthe proper optimum engine operating temperature is reached when throttle22 will be at its normal slow idling position. At such time idlingmixture will be drawn solely through port 43.

During all idling periods when throttle `22 is closed, the idling vacuumwill befapplied through the small orifice 39 to the top of valve 35 thusraising the same from its seat in passage 28 against the resistance ofspring 31, but this raising of valve 35 does not become fully effectiveuntil choke valve 10 is at least partially open whereby sufficientdifference in pressure will exist between the upper and lower sides ofthe head of valve 35 to raise the same.

Also such idling vacuums are applied through the small port 65 to beapplied to tube 62 whereby liquid fuel is raised therein to apredetermined height below the level of spindle 46, said height beingdetermined by the size of 'the -air bleed passage 88, the highestposition of the liquid column in tube 62 being when throttle 22 isclosed for idling speeds.

Now upon opening throttle 22 to any degree for increased speed of engineI0 (valve 10 being open), the vacuum on the engine side of throttle 22will decrease while the vacuum in mixing chamber 2| will increase to theend that no mixture will be drawn through orifice 43 but mixture will bedrawn in the properamount and proportion from nozzle 30, the volumebeing governed by the degree of engine suction, applied and intensifiedthrough the action of the venturis 3| and 33, and the proportion of airto liquid fuel being controlled in the initial opening stage of throttle22 by the action of valve 35.

Valve 35 is arranged to be seated in passage 28 and cut oif the supplyof air therethrough when throttle 22 is aboutl one-quarter open exceptfor a very small amount `which may pass through a calibrated orifice 34atherein. This supply of secondary air mixing in fitting 21 through aplurality of ports 21a gives fine atomizing eects on the liquid fuelsupplied through passage 26 and also regulates the effect of the suctionapplied through nozzle 30 so that proper and economical proportions aremaintained in the mixture atall operating speeds and loads other thanidling.

The passage of air from passage I6 through port 34 and passage 28 to thesecondary mixing chamber 29 will be better understood when it isexplained that passage I6 is normally of greater diameter than mixingchamber 2|. Also any vacuum induced at the throat of venturi 3| will begreater than the vacuum in passage I6 at any engine speed., thereforethere will always be a circulation of air from passage I6 through port34 and passage 28 to the nozzle 3|). Anequivalent effect for airbleeding nozzle 30 may be obtained by closing the port 34 to passage I6and transferring the position of the same to a wall ofcylinder 36 whereit will open to air on the lower side of the head of valve 35, but thepresent and described location of port 24 is preferred because atstarting periods there will be no flow of air from passage |6, thusleaving the rich priming charge from nozzle 38 undiluted.

The discharge of liquid fuel from accelerating well 6| occurs at thecontinued opening of throttle 22 but is particularly effective upon thesudden opening oi' throttle 22 from closed to open position. When thisoccurs, the vacuum at port 65 will drop from say 22 inches of mercury atidling to one-half inch of mercury at wide open throttle. This causesthe column of liquid fuel held in tube 62 to fall and flll the annularspace 66 above the level of the passage 68 a predetermined distance sothat the excess above that level will discharge through orifice 69 tothere mix with the air stream now passing at high velocity throughventuri 3|. In this manner the inertia of the liquid fuel suppliedthrough passage 26 is compensated formomentarily.

During normal running there may be insufcient difference in vacuum oneither side of choke valve 1|) to cause a diversionv of sumcient heatedair around thermostat 18 and for this reason standpipe 81 is providedwith one edge cut away at 86 to receive the impact of the air stream,thus forcing the heated air through casing 14 to act on thermostat 18and hold valve 18 open, the limit of opening being its horizontalposition when one side thereof rests on the top of pipe 81. v

At low temperatures and after starting as described, if it be desired toaccelerate, increased richness of mixture is provided for because of thepartially closed position of choke valve 18 thus throwing abnormalsuction on nozzle 30 until engine Il) approaches optimum temperatureconditions when valve 18 will be further opened and the abnormal suctionon nozzle reduced.

With certain types of engines, the priming charge induced through nozzle30 as already described is insufficient for the quickest and mostdesirable start and therefore, in addition to the choking means alreadydescribed, further priming means are provided more particularlyillustrated in Figs. 8 and 9. In Fig. 8, a lever 94 is fastened tospindle 1| at one end, the other end supporting a valve 95 adapted to beresiliently seated in passage 88 by the pressure of a spring 96, thisbeing in order that choke valve 10 may be fully closed as well as valve95. When this happens at starting periods, atmosphere is cut olf frompassage 88 by valve 95 to the end that a high cranking vacuum is appliedto through orifice 65 and a stream of liquid fuel is drawn therethroughfrom tube 62. This additional stream of fuel'aids the quick starting ofengine I8 and after starting valve 95 still is held closing passage 88because of a certain amount of lost motion between the end of lever 94and the head of valve 95.

Thus additional fuel is supplied for starting and for running for alimited time thereafter until the continued opening of choke valve 10causes lever 94 to engage the, head of valve 95' and start to openpassage 88. This action reduces the amount of fuel drawn through orifice65 because air is now being admitted to passage 88 until passage 88 iswide `open at optimum operating temperatures.

Another function of valve 95 is to be noted. While fuel is .being drawnthrough orice 65, as described, the liquid level in tube 62 will beraised above normal so that when throttle 22 is suddenly opened atsubnormal operating temperatures, an additional amount of acceleratingcharge will be supplied from well 6| to orice 69.

An alternative construction is shown in Fig. 9, wherein a thermostaticspring encircles valve 95, being held in spaced relation to the headthereof by a nut 98. Thermostat 91 is responsive to the heated airsurrounding engine l0, more particularly when the same is placed underthe hood of an automobile, and operates to open valve 95 with increasingtemperatures of engine i6.

A modification of dashpot 54 is shown in Fig. 4, wherein choke valve 18is placed in the center of passage I6 and holes 59 extend up to the headof stem 56. At starting, therefore, valve 1li will be tightly closed andthe engine suction will raise piston 55 and lever 52 a predetermineddistance until certain of the holes 59 will be exposed to atmospherethereby breaking the vacuum applied through stem 56 to the upper part ofpiston 55 until equilibrium is reached.

I'he air thus supplied through stem 55 to passage I0 takes' the place ofthat supplied by the sudden jump of valve 10 when the same is placed offcenter and, as valve 10 now gradually opens with increasingtemperatures, piston 55 will gradually fall and cut oiI more of theholes 59 until all are cut off from atmosphere at optimum operatingtemperatures.

Fig. rI shows an alternative construction for the upper part of Fig. 5wherein throttle arm 48 is firmly fastened to spindle 45 and spindle 46supports lever 52 on the same side as arm 4B. The tension of spring 92is now so calibrated as to permit the limited opening of throttle 22 atstarting as already described for fast idling and this constructionpermits the easy installation of apparatus shown in Fig. 8, if sodesired.

Fig. 13 shows a modification of Figs. 5 and '1 wherein a lever 99 isfixed to spindle 1| and connected by a link |00 to a lever |0| fastenedcentrally to spindle 46. Link |00 has a head |02 sliding through a slot|03 in lever |0| and held therein by a. pin |04 which is adapted to holdon lever I0| at starting periods for opening throttle 22 a predeterminedamount against the re' sistance of a spring |05, said spring holdingthrottle 22 closed at idling position at optimum operating temperatures.

When choke valve 10 is closed, the action of thermostat 18 will causelink |00 -to pull on lever |0| to hold throttle 22 open a certaindistance for fast idling, thereafter as the temperature of engine I0increases, valve 10 will gradually open and permit throttle 22 togradually close. At any time throttle 22 may be fully opened,irrespective of the position of valve 10 because link |00 can freelyslide through slot |03.

Fig. 16 shows a modification of Figs. 15 and 14. wherein the stove i4 isconnecte-d by a comparatively small pipe l5 to the interior of casing 14thence to the manifold on the engine side of throttle 22. Thisconstruction is provided in such cases as when the carbureter I3 is notsupplied with hot air when passages 02 and 84 are plugged and heated airis drawn over thermostat 1B through pipe I5. The entry of pipe I5 tomanifold is through'a small orice about the size of a #70 drill whenpipe i5 is one quarter inch internal diameter, but these comparativesizes may be varied with the capacity of engine I0 so as not to affectthe idling mixture.

Figs. 17 and 18 show an alternative construction for Figs. 14, 15 and 16wherein the heated exhaust gases are conveyed` by Atheir pressure fromthe interior of pipe |2 through pipe I5 to the interior of casing 14wherein they heat thermostat 18 and pass to atmosphere through aplurality of holes |08, the entry of pipe I5 in exhaust pipe |12 facingin the direction of the flow of exhaust gases therethrough.

The entry of pipe I5 to casing 14 is controlled by a sector |06,Ifastened to spindle 1|, having a tapered slot |01 therethrough to theend that pipe |5 may be fully opened to casing 14 at idling speeds andthereafter will be gradually reduced in opening at higher speeds whenthe exhaust gases are at a higher temperature. This action preventsexcessive strains being applied to thermostat 18, due to excessive heatat high speeds.

By the various ldispositions and constructions shown and described, itwill be seen that a very rich mixture will be drawn into engine- I0initially by its suction, both Kby priming and choking. suddenly reducedto a rich mixture after tiring and thereafter gradually reduced tonormal as engine |0 arrives at normal and opti.- mum operatingtemperature. The additional priming charge for starting is providedthrough orice 65, which may vary in size for automobile engines from a#70 to a #60 drill hole, while the choking means causea restriction inthe supply of air as well as increasing the flow of fuel from nozzle 30.In the present case it will be seen that the additional priming supplymay be dependent on the action of the choking means.

For any particular engine |0, the tension of spiral thermostatic spring1B may be adjusted by loosening screw 10 and turning casing 14 untilchoke valve 10 is in the proper position when screw 'I9 is again madetight.

I claim:

l. In a carbureter for supplyinga mixture of air and fuel to a connectedinternal combustion engine, a throttle for controlling the mixture,means normally tending to close the throttle, and suction operated meansand means controlled thereby for partially opening the throttle whenstarting the engine.

2. In a carbureter for supplying a mixture of air and fuel to aconnected internal combustion engine, a throttle for controlling themixture, means normally tending to close the throttle, means actuatedbythe engine suction and means controlled thereby for maintaining thethrottle slightly open when starting the engine.

3. In a suction operated carbureter, a main air passage having athrottle therein, a discharge passage having a throttle therein, a fuelsupply passage discharging between said throttles and means connectedbetween said throttles and effected by engine suction for .automaticallyopening the discharge throttle.

4. In a suction operated carbureter, a main air passage having athrottle therein, a discharge passage having a throttle therein, a fuelsupply passage discharging between said throttles and suction operatedmeans connected between said throttles and means controlled thereby forautomatically opening the discharge throttle.

5. In a carbureter for supplying a mixture of air and fuel to aconnected engine by its suction, a discharge throttle, means normallysetting the discharge throttle to supply a minimumvolume of said mixtureto the engine when idling, suction operated means and means controlledthereby to open said throttle to automatically increase the volume ofsaid mixture when starting the engine.

6. In a carbureter for supplying a mixture of air and fuel to a`connected engine by its suction, a discharge throttle, means normallysetting the discharge throttle to supply a minimum volume of saidmixture to the engine when idling, suction operated means and meanscontrolled thereby to open said throttle to automatically andtemporarily increase the volume of said mixture when vstarting theengine.

'1. In a carbureter for supplying a mixture of air and fuel to aconnected engine by its suction, a discharge throttle normally set tosupply yclicking throttle in' the air passage, a mixing chamber, adischarge throttle governing thedischarge from the mixing chamber, afuel nozzle discharging into the mixing chambenand means dependent onthe closing of the choking throttle and effected by engine suction foropening the discharge throttle.

9. The combination of an internal combustion engine having a passage forsupplying fuel and air thereto, means to supply fuel and air to thepassage, a throttle in said passage governing the supply of saidmixture, and suction operated means actuated by engine suction and meansacted upon by enginetemperature to effect said suc- Ition means forvarying the position of said throttle. l

10. The combination of an internal combustion engine, a carbureter, apassage through the carbureter for supplying the engine with a mixtureof fuel and air by engine vacuum, a. nozzle discharging into saidpassage, means to supply fuel to the nozzle, a throttle in the passageposterior to the nozzle, an anterior throttle in the passage, and meansassociated respectively with said posterior and anterior throttles anddependent on the vacuum between said throttles for varying the positionof both throttles.

11. The combination of an internal combustion engine, a carbureter, apassage through the carbureter for supplying the engine with a mixtureof fuel and air by engine vacuum, a nozzle discharging into saidpassage, means'to supply fuel to the'nozzle, a throttle in the passageposterior to the nozzle, an anterior throttle in the passage, and meansassociated respectively with said posterior and anterior throttles anddependent on the vacuum between said throttles and on engine temperaturefor varying the position of both throttles.

l2. The method of regulating the supply of fuel and air to an internalcombustion engine which comprises supplying aV very rich mixture ofcomparatively large volume to the engine by its vacuum at starting,firing the mixture whereby a sudden increase in vacuum occurs, thenutilizing the sudden increase in vacuum to suddenly decrease therichness of the mixture and thereafter gradually decreasing the volumesupplied while decreasing the proportion of fuel to air according toengine suction.

13. The method of regulating the supply of fuel and air to an internalcombustion engine which' comprises supplying a very rich mixture ofcomparatively large volume to the engine by its vacuum at starting,firing the mixture whereby a sudden increase in vacuum occurs, utilizingthe sudden increase i vacuum to initially decrease the richness of themixture and thereafter utilizing the engine temperature to graduallydecrease the volume supplied and to further decrease the richness of themixture while,` decreas- -ing the proportion of fuel to air. l

14. The method of regulating the supply of fuel and air to an internalcombustion engine which comprises'suppl'ying a mixture of fuel and airto the engine in comparatively large volume, the proportion of fuel toair being comparatively high, then gradually reducing the volumesupplied while reducing the proportion of fuel to air according to theengine suction.

15. The method of regulating the supply of fuel and air to an internalcombustion engine which comprises supplying a mixture of fuel land airto the engine in comparatively large volume,

the proportion of fuel to air being comparatively y.

high, then gradually reducing the volume supplied while reducing theproportion of fuel to air according to the engine temperature.

16. The method of regulating` the supply of fuel and air to an internalcombustion engine which comprises supplying a mixture of fuel and air tothe engine in comparatively large volume, the proportion of fuel to airbeing comparatively high, then gradually reducing the volume suppliedWhile reducing the proportion of fuel to air according to thel enginesuction and temperature.

1'7. A carbureter having a constant level fuel supply chamber, a mixingchamber, means to supply air to the mixing chamber, a throttle governingthe discharge from the mixing chamber, a well fed with liquid fuel fromthe supply charnber and discharging into the mixing chamber, meansconnected with the mixing chamber on one side of said throttle to raisethe liquid level in the well above the constant liquid level in thechamber, and means to automatically vary the liquid level in the welldepending'on temperature.

18.v A carbureter having a constant level fuel supply chamber, a mixingchamber, means to supply air to the mixing chamber, a throttle governingthe discharge from the mixing chamber, a well fed with liquid fuel fromthe supply chamber and discharging into the mixing chamber, meansconnecting with the mixing chamber on one side of said throttle to raisethe liquid level in the well above the constant liquid level in thechamber, and means to vautomatically vary the liquid level in the welland discharge the liquid fuel therein to the mixingv chamber on eitherside of said throttle.

19. In a plain tube carbureter, means forming a mixing conduit, an airinlet and a fuel inlet for said mixing conduit, an air inlet valvemounted in said air inlet, said air inlet valve being so mounted as tobe openable in response to suction, a heat responsive device foryieldably closing said valve when the temperature is below normal, saidheat responsive device being constructed and arranged to hold said valvein a fixed open position regardless of variations in suction wheneverthe temperature is at or above normal.

20. In a carbureter, means forming a mixing conduit, an air inlet and afuel inlet for said mixing conduit, a choke valve, said fuel inletdischarging into said mixing conduit at a point posterior to said chokevalve, said choke valve being concentrically mounted in said air inletwhereby it may be moved toward open position by suction, and a heatresponsive device for closing said choke valve when the temperature isbelow normal, said heat responsive device being constructed and arrangedto permit the movement of said choke valve to fully open positionwhenever the temperature is at or above normal, said choke valveremaining in fully open position regardless of variations in eithersuction or temp'erature as long as the temperature does not fall belownormal.

21. In a plain tube carbureter, means forming a mixing conduit, a singlemain air inlet and a fuel inlet for said mixing conduit, said air inletbeing of constant size regardless of suction during normal temperatureoperation, a valve for controlling said air inlet to enrich the mixturewhenever the temperature-is below normal, heat responsive means foroperating said valve, said valve being constructed and arranged to bedirectly acted on by suction when it is in mixture-enriching positionand being displaced by suction in a direction to cause a leaner mixtureto be delivered by the carbureter.

22. In a carburetor, means forming a mixing conduit, said mixing conduithaving an air inlet, a fuel inlet, and a mixture outlet, a manuallyoperable throttle valve controlling said mixture outlet, a choke valvecontrolling said air inlet. a heat responsive device controlling theposition of said choke valve, and means connected to said choke valvefor preventing the movement of said throttle valve to fully closedposition while said choke valve is in fully closed position.

23. In a plain tube carbureter. means forming a mixing conduit, saidmixing conduit having an air inlet and a fuel inlet and a mixtureoutlet, a manually operable throttle valve controlling said mixtureoutlet, an eccentrically mounted choke valve controlling said air inlet,a heat responsive device for closing said choke valve when thetemperature is below normal, said heat responsive device beingconstructed and arranged to permit the Ychoke valve to move to fullyopen position as soon as the temperature reaches normal and to remain infully open position regardless of temperature variations above normal,and connections between said choke valve and said throttle valve forpreventing the movement of said throttle valve to fully closed positionas long as said choke valve is in fully closed position.

2'4. In a carbureter, means forming a mixing conduit, said mixingconduit having an air inlet, a fuel inlet and a mixture outlet, amanually operable throttle valve controlling said mixture outlet and aheat responsive device for interfering with the closing of said throttlevalve when the temperature is below normal.

25. In a carbureter, means forming a mixing conduit, said mixing conduithaving an air inlet, a fuel inlet and a mixture outlet, a manuallyoperable throttle valve controlling said mixture outlet and a heatresponsive device for at least partially opening said throttle valvewhen the temperature is below normal.

26. In a carbureter, means forming a mixing conduit, said mixing conduithaving an air inlet, a fuel inlet and a mixture outlet, a choke valvecontrolling said air inlet and a throttle valve controlling said mixtureoutlet, a heat responsive device for controlling said choke valve, and asuction responsive device for controlling said throttle valve.

27. In a plain tube carbureter, means forming a mixing conduit, saidmixing conduit having an air inlet, a fuel inlet and a mixture outlet, athrottle valve controlling said mixture outlet, a choke valvecontrolling said air inlet, means for operating said choke valve inresponse to heat and suction and for holding said choke valve in a fixedopen position regardless of suction whenever the temperature is at orabove normal, and means responsive to both heat and suction forcontrolling the position of said throttle valve.

28. Inan internal combustion engine having an intake manifold, and anexhaust manifold;

a carbureter having an air inlet and a fuel outlet, a, choke valvemounted in said air inlet, a throttle valve mounted in said outlet, saidchoke valve having a shaft, a heat responsive element mounted at one endof said shaft, a housing for said heat responsive element, a. passagewayconnecting said housing to said air inlet whereby at least some suctionis applied to said housing, a conduit for conveying heated gaseous fluidfrom said exhaust manifold to said housing, valve means controlled bysaid shaft for regulating the flow of said heated gaseous uid throughsaid housing, and means operable from said shaft for preventing closingof the throttle valve.

29. In an internal combustion engine having an intake manifold andanexhaust manifold; a carbureter attached to said inlet manifold, saidcarbureter having an air inlet, a fuel inlet and a mixture outlet, athrottle valve controlling said mixture outlet, a choke valvecontrolling said air inlet, a heat responsive element connected to saidchoke valve, a housing for said heat responsive element, an air heatingstove mounted on said exhaust pipe, a conduit leading from said airheating stove to said housing, and another conduit leading from saidhousing to said intake manifold at a point posterior to said throttle.

30. In an internal combustion engine having an intake manifold and anexhaust manifold, a carbureter attached to said inlet manifold, saidcarbureter having an air inlet, a fuel inlet and a mixture outlet, athrottle valve controlling said mixture outlet, a choke valvecontrolling said air inlet, a heat responsive element connected t saidchoke valve, a housing for said heat responsive element, an air heatingstove mounted on said exhaust pipe, a conduit leading from said airheating stove to said housing, and another conduit leading from saidhousing to said intake manifold at a point posterior to said throttle,and valve means operatively connected to said heat responsive device forcontrolling the flow of heated air through said housing.

31. In an internal combustion engine, an ini duction passage, acarbureter constituting part of said induction passage and having an airinlet and an air outlet, a choke valve mounted in said air inlet, athrottle valve mounted in said outlet, said choke valve having a shaftprojecting from one side of said air inlet, a heat responsive ele mentmounted at said end of said shaft, a housing for said heat responsiveelement, a. conduit for conveying heated gaseous fluid to said housingto heat said element, said housing having an outlet to said inductionpassage posterior to said choke valve, and means controlled by saidshaft for preventing closing of the throttle valve when starting theengine.

32. In an internal combustion engine having an induction passage and anexhaust manifold,

l a carbureter constituting part of said induction passage, a. chokevalve in said carbureter, a throttle valve in said carbureter, saidchoke valve having a shaft, a heat responsive element at one end of saidshaft, a housing for said heat responsive element, a passagewayconnecting said housing to said induction passage posterior to saidchoke valve whereby suction is applied to said housing, a conduit forconveying heated gaseous fluid from a point adjacent said exhaustmani--4 fold to said housing, and means operable by said heat responsiveelement controlling the closing of the throttle valve.

33. In a carbureter for supplying a mixture of air and fuel to aconnected internal combustion engine, a, throttle for controlling themixture supply, thermo-responsive means, and means controlled therebyfor preventing closing of the` said means being controlled by the airintake throttle.

35. In a carbureter, a main air intake having a throttle therein,thermo-responsive means controlling said throttle, a discharge passagehaving a throttle therein, means operated by suction between saidthrottles, and means controlled thereby for preventing closing oi' thedischarge throttle, and a' fuel supply e discharging 10 between saidthrottles.

36. In a carbureter for an internal combustion engine, a discharge valvenormally set to supply idling mixture when the engine is hot, a chokevalve, thermo-responsive means controlling'said choke valve, and meanshaving a.v free connection lwith one of said valves, and controlled bythe choke valve to prevent movement of the discharge valve to ,normalhot idling position, while the engine is cold.

' CHARLES L. STOKES.

